Process of making rough plate-glass.



No. 628,!20. Patented July 4, I899. P SEMMER. PROCESS OF MAKING ROUGHPLATE GLASS.

(Application filedfi Aug. 31, 1898.)

(No Model.)

f/ZZZZ Mme/x i UNITED STATES PATENT OFFICE.

PHILLIP SEMMER, OF IRWIN, PENNSYLVANIA, ASSIGNOR TO MARY CAROLINESEMMER.

PROCESS OF MAKING IROUGH PLATE-GLASS.

SPECIFICATION forming part of Letters Patent No. 628,120, dated July 4,1899.

Application filed August 31,1898. Serial No- 689,953. 7(N0 specimens.)

To ctZZ whom it may concern.-

Be it known that I, PHILLIP SEMMER, a citizen of the United States,residing at Irwin, in the county of WVestmoreland and State ofPennsylvania, have invented certain new and useful Improvements inProcesses of Making Rough Plate-Glass; and I do hereby declare thefollowing to be a full, clear, and exact description of the invention,such as will enable others skilled in the art to which it appertains tomake and use the same.

My invention has-relation to the process of making rough plate-glass forgrinding and polishing purposes. In the manufacture of glass for thispurpose the present practice is to either cast the molten glass on theend of a polished iron table and roll it into glass of required size andthickness or to gather the metal on the end of a blowpipe and blow thesame into long cylinders, which are then split and flattened into sheetswith the aid of a wooden flattening-block. Neither of these processesresults in absolute fiat sheets. The dragging of the iron roller and thewooden flattening-blocks over the top of the glass produces an unevenand wavy surface, requiring additional labor in the process of grindingthe plates to a true plane. The object of my present invention is toproduce absolutely fiat and approximately round plates of glass forgrinding and polishing purposes without restriction to size andthickness, with a vitriformed edge adapted to fully cover a roundgrinding-table and guard and protect the edge of the glass plate withthe vitriformed or unbroken fire-finished edge against breakage whencemented to the grinding-table and subjected to the grinding process.

In the accompanying drawings, Figure l is a side elevation, partly insection, of the table and plunger for forming the sheet of glass.

Fig. 2 is a top plan of the table.

The machinery necessary to accomplish my process consists of a table 1and a reciprocating plunger 2, located above the table, said plungerbeing adapted to be operated by any suitable means, preferably byhydraulic pressure. The under face of the plunger is preferably smoothand is flat and highly polished, the plunger being of the samedimensions as the table. The molding-ring 3 is adapted to be placed ontop of the table 1 in the center of the same, as indicated in thedrawings.

The said ring 3 may be provided with suitable handles, as indicated bydotted lines, for readily removing the same. I do not, however, confinemyself to the use of this ring, as it is obvious thatan ordinary ladlefull of glass cast in the center of the table for this purpose in acircular form pressed uniformly in common directions will also forman'approximately round plate of glass.

The process is as follows: The plunger is elevated. The ring 3 is placedin position in the center of the table-top 1, or the glass is cast inthe center of the table-top, as above indicated. WVhen the ring is used,the molten glass is poured into the ring. The ring is thenremoved andthe plunger 2 is caused to descend, and the batch of glass is thuspressed in equal directions and is flattened out on top of the table 1.The sheet thus formed is approximately a round disk of glass, and the"disk may be pressed out and given any required thickness. It will thusbe seen that the resultant sheet of glass will be absolutely fiat onboth sides and is in proper condition for grinding and polishing, asabove set fort-h. The edge of the glass so formed is unbroken andvitriformed or fire-finished. The sheet may be secured to the top of around grinding and polishing table by means of cementing the vitriformededge to the table; Thus the plate is not exposed to the danger ofcracking, which occurs in exposing the raw diamond-cut edge of the glassplate for this purpose.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. The process of producing sheets of glass, consisting in casting themolten glass in a bottomless mold on a flat table, then removing themold and pressing the glass between a flat surface and the table,substantially as described.

2. The process of producing flat sheets of glass, consisting in castingthe molten glass in a bottomless mold on a flat table, then re movingthe mold and pressing the glass between a flat surface and the table,then making unbroken vitriformed or fire -finished moving the mold andpressing the glass to the edges to the glass, substantially asdescribed. desired thickness by a vertically-reciprocat- 3. The processof producing an approxiing plunger provided with a smooth and flatmately round sheet of glass with an unbroken contact-face, substantiallyas described. I 5 5 fire-finished edge, consisting in casting the Intestimony whereof I aifix my signature molten glass on a table andpressing the same in presence of two witnesses. between fiat surfaces tothe required thickness, substantially as described. PHILLIP SEMMER' 4.The process of producing flat sheets of Witnesses: 10 glass, consistingof casting the molten glass EMIL FISCHER, in a bottomless mold on a flattable, then rc- I. BALEZER.

